Base-referencing lamp-holder and projection lamp



June 2, 1970 D. M. WAGNER 3,515,042

BASE-REFERENCING LAMP-HOLDER AND PROJECTION LAMP Filed Jan. 8, 1968 2 Sheets-Sheet 1 lnveenfiov: Do'rwaLd M wa cgner by M122. 2%,, His Attiorne June 2, 1910 D. M. WAGNER 3,516,042

BASE-REFERENCING LAMP-HOLDER AND PROJECTION LAMP Filed Jan. 8; 1968 2 she'ets -sheet 2 lnven tor: DonaLd M. Wagner His A t torneg United States Patent US. Cl. 339-45 Claims ABSTRACT OF THE DISCLOSURE A lamp-holder is provided for use in combination with a prefocused bipin lamp which has a specially designed base. The lamp-holder fixes the msition of the lamp with reference to the base by clamping the base against a reference bracket by means of a resilient bracket, each of which brackets is essentially perpendicular to the face of the socket of the lamp-holder. Suitable electrical contacts for the two pins of the lamp are provided within the socket, and access openings to such contacts are provided in the face of the socket. A lever permits ready removal of the lampfrom the lamp-holder without the necessity of firmly grasping the lamp by hand. The base of the lamp of the invention is provided with a locater pad and a positioning pad which spring load the lamp into position in the lamp-holder. The present invention is particularly useful in overhead projectors, slide projectors and motion picture projectors.

BACKGROUND OF THE INVENTION The present invention relates to base-referencing lampholders in combination with projection lamps. More specifically, it relates to such lamp-holders for referencing bipin lamps by fixing the position of the base of the lamp.

Previously available lamp-holders and lamp combinations, such as for certain types of projectors, have not been entirely suitable in their means for controlling position of the lamp. Position of a lamp within a lamp-holder in a projection system is, of course, critical to eflicient light control and optimum results with the projector. Some systems require first fixing the lamp in a holder and then plugging on electrical contacts, and others provide for these two steps in a reverse order. Still other systems control the position of the bipin lamp merely by plugging it firmly into a socket and letting the electrical contact pins and the socket interact to control the position of the lamp.

It would be desirable to have a lamp holder and lamp system suitable for use in motion picture projectors wherein the lamp could be simply inserted and firmly positioned by positive referencing means by one simple motion. Further, it would be desirable to be able to remove such lamps from their lamp-holders while the lamps are still hot, without having to grasp them firmly by hand.

:SUMMARY OF THE INVENTION It is an object of the present invention to provide a lamp-holder and lamp combination suitable for use in overhead projectors, slide projectors, and motion picture projectors wherein the lamp can be inserted into the lampholder and its position referenced relative to the lampholder in one simple motion. A further object is to provide such combinations wherein positive position referencing forces are applied to the base of the lamp to hold it in place. A further object is to provide such combinations wherein the lamps can be removed from the lampholders while hotwithout the necessity of grasping the lamps firmly by hand.

Briefly stated, the present invention in certain of its embodiments provides a lamp-holder having a socket, a

3,516,042 Patented June 2, 1970 reference bracket, and a resilient bracket, with said brackets adapted to firmly hold in place a bipin lamp having a suitably designed base. The resilient bracket is preferably provided with a lead-in angle to guide the lamp base down into the socket, and also preferably has a holddown member adapted to push the lamp base down onto the socket and hold it there firmly, when the lamp is in place. The resilient bracket is also adapted to push the lamp base against the reference bracket and hold it there firmly. Either the reference bracket or the resilient bracket or both may be provided with means such as indexing fingers or openings to prevent transverse motion of the lamp parallel to the brackets and parallel to the face of the socket. In one form, the reference bracket has two rigid vertical fingers with lead-in angles at their upper ends. These fingers prevent transverse motion of the lamp base when they interact with a locater pad on the side of the lamp base which faces the reference bracket. A positioning pad on the side of the lamp base facing the resilient bracket fits within the resilient bracket, and the locater pad on the other side of the base slides into the reference bracket to hold the lamp firmly in position.

The socket has openings in its face to permit the bipin contacts of the lamp to enter into the socket and make electrical contact with resilient electrical contacts which are inside the socket.

In one embodiment of the invention, lamp ejector means are provided, preferably in the form of a lever pivotally mounted on the lamp-holder.

The lamp-holders and lamps each are subcombinations of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a rear elevation view of a lamp-holder and lamp of the invention, with the lamp inserted in position, and also showing a lamp ejector.

FIG. 2 is a side view of the same subject as FIG. 1. FIG. 2A is a detail of FIG. 2, partly in section and showing the construction of the resilient bracket of the lampholder.

FIG. 3 is a front elevation view, showing the invention from the side opposite that of FIG. 1. The front of the lamp is the side through which light is preferably projected.

FIG. 4 is a front elevation view of a lamp-holder and lamp of the invention with the lamp having just been ejected by the lamp ejector. The front portion of the socket and the reference bracket have been removed to better illustrate the inner portions of the socket.

FIG. 5 is a sectional top plan view of the lamp-holder of the invention, showing the resilient electrical contacts.

FIG. 6 is an exploded View of one embodiment of the lamp-holder of the invention, showing the electrical contacts exiting from the sides of the socket.

FIG. 7 is the same as FIG. 6 except that it shows another embodiment of the invention in which the contacts exit at the bottom of the socket, opposite the face at which the lamp is inserted.

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DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to the drawings, FIGS. 1 and 2 generally illustrate the combination of the invention made up of a lamp-holder indicated at 1 and a lamp indicated at 2 in FIG. 1. The lamp-holder has a reference bracket 4, shown in FIGS. 2, 3 and 4 and a resilient bracket 3 which spring loads the lamp base 10 against reference bracket 4 and against socket 5. Socket 5, made of suitable insulating materials such as ceramics, with its component parts and lever 6 constitute the other main parts of the lampholder.

Lamp 2 comprises base 10, bulb 14 and filament 13. The lamp is prefocused so that its light source, in this case filament 13, is fixed at a predetermined location relative to base 10 when the lamp is made. This permits controlling the position of the lamp relative to the lampholder by fixing the position of the base in the lampholder. The lamp illustrated is a compact incandescent lamp, preferably of the type known as a quartz-halogen lamp, having a regenerative cycle to prevent bulb blackening and lengthen the life of filament 13. Lamps of the invention have bipin contacts 11 and 12, best seen in FIG. 4 where the lamp has been ejected from the lamp-holder. Pin 11 is smaller in diameter than pin 12, and the corresponding holes 33 and 34 and resilient electrical contacts 7 at 7A and 8 at 8A, respectively, in socket 5 are of the right sizes to accommodate these different-sized pins and assure that the lamp will not be placed in the lamp-holder in a reversed position. The correct position of the lamp can depend on the configuration of the filament and the location of any reflecting surfaces on the lamp, not shown here. Preferably, contacts 7A and 8A grasp pins 11 and 12 firmly for optimum electrical contact, but contacts 7, 7A, and 8, 8A fit loosely in socket 5 so that positioning of lamp 2 can be more effectively controlled by reference bracket 4 and positioning bracket 3 acting on base Electric contacts 7 and 8 preferably are adapted to fit industrial standard push-on terminal fittings for electrically connecting the lamp-holder of the invention With the circuits of the apparatus in which it is to be used, such as a projector. Other readily apparent alternative constructions include extending socket 5 to the sides to cover contacts 7 and 8 and providing cavities in socket 5 for attaching the terminals of the apparatus.

Base 10 is preferably provided with a locater pad 19 on the side of socket 10 which faces reference bracket 4. The vertical edges of locater pad 19 butt up against vertical fingers 20 and 21 of reference bracket 4 to prevent transverse motion of the lamp parallel to bracket 4 and parallel to face of socket 5. The ridge shown on finger 20 stiffens that finger, but it can be omitted if desired to facilitate mounting ejection lever 6 on the side of lamp-holder 1 opposite to that illustrated in FIGS. 3 and 4.

The opposite side of base 10 has a positioning pad 15, preferably with a positioning chamfer 16 at its top, configurated so as to be pushed by hold-down member 17 of resilient bracket 3 to hold the lamp base more firmly spring loaded and seated down onto socket 10 and flush against positioning bracket 4. Hold-down member 17 is bent at an angle less than 90 to the side of socket 5 and less than 90 to the face 35 of socket 5, and is adapted to exert forces on base 10 toward face 35 and toward reference bracket 4 when lamp 2 is in operating position in lamp-holder 1. The bottom of socket 10 is positioned accurately on face 35 of socket 5 by three lugs 22A, 22B and 22C, giving a tripod-like stability, particularly in combination with the spring loading of base 10 onto socket 5 by hold-down member 17 of resilient bracket 3. Alternatively, four or more lugs could be used instead of the three lugs 22A, and 22B and 22C.

Lead-in relief angles are built into resilient bracket 3 at 3A and into reference bracket 4 at 4A to facilitate insertion of the lamp into the lampholder.

Socket 5 is preferably made of two essentially symmetrical halves 24 and 25. These halves 24 and 25 are held together by rivets 26 and 27 through holes 26A and 27A in the reference bracket 4, resilient bracket 3, and the halves 24 and 25 themselves, and positioning lugs and holes 18 assure proper alignment of the socket halves 24 and 25. Bracket lugs 28 on each half 24 and 25 of socket 5 align with lug holes 29 in reference bracket 4 and resilient bracket 3 to assure proper alignment of those brackets with socket 5.

An alternative design of socket 32 is shown in FIG. 7

4 wherein the terminal contacts 30 and 31 leave socket 32 at its bottom rather than its sides. Holes 33 and 34 and contacts 30A and 31A in socket 32 serve the same function as the corresponding parts in socket 5.

Ejection lever 6 is pivoted on the brackets at 9, or could alternatively be pivoted at 9A if there was more room in the projector on that side. As the outer end of lever 6 is moved downwardly, portion 6A disengages the lamp from the socket. This eliminates the necessity of firmly grasping a hot lamp by hand to pull it from the lamp-holder, such as to change a burned-out lamp quick- 1y for minimum disruption of a picture being shown. Also, it makes it easier for the operator to handle the lamp by the base, avoiding getting fingerprints on the bulb which could lead to devitrification of the quartz bulb 14. What I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination of a lamp-holder comprising a socket, a reference bracket, and a resilient bracket, said socket having a face and two opposed sides and having electrical contacts within said socket behind said face, said reference bracket and said resilient bracket being mounted one on each of said opposed sides of said socket and extending beyond said face and essentially perpendicular to said face, said face having openings adapted to allow electrical contact pins of a lamp to make contact with said electrical contacts within said socket, said resilient bracket comprising means being adapted to apply a force on the base of said lamp towards said reference bracket to maintain said lamp in a predetermined position relative to said reference bracket, and means adapted to exert a force on said lamp base toward said socket to hold said lamp in said socket, and a prefocused lamp comprising a bulb, a base, and two pins serving as electrical inleads, said pins being adapted to make electrical contact with said electrical contacts within said socket, said base comprising means adapted to permit said resilient bracket to hold said lamp in said socket and against said reference bracket so that the light source of said lamp is held in a predetermined position relative to said lampholder. 2. The combination of claim 1 including lamp ejector means comprising a lever pivoted relative to said lamp-holder and adapted to move said lamp out of said lamp-holder when said lever is moved in a predetermined manner.

3. The combination of claim 1 wherein at least one of said reference bracket and said resilient bracket comprises an entry portion bent outwardly from the face of said socket and adapted to lead said base of said lamp into position in said lamp-holder, and

said resilient bracket comprises a hold-down member bent at an angle less than to said side wall and less than 90 to said face, and adapted to exert forces upon said base towards said face and towards said reference bracket when said lamp is in position in said lamp-holder, and

said base of said lamp has a protruding mounting pad on the side which fits against said resilient bracket, said pad being adapted to interact with said holddown member to exert forces on said lamp base toward said socket and toward said reference bracket.

4. The combination of claim 1 wherein at least one of said resilient bracket and said reference bracket are provided with means to interact with said baseto prevent transverse movement of said lamp parallel to said brackets and parallel to said face when said lamp is in position in said lampholder.

5. The combination of a lamp-holder comprising a socket, a reference bracket, and a resilient bracket, said socket having a face and two opposed sides and having electrical contacts within said socket behind said face, said reference bracket and said resilient bracket being mounted one on each of said opposed sides of said socket and extending beyond said face and essentially perpendicular to said face, said face having openings adapted to allow electrical contact pins of a lamp to make contact with said electrical contacts within said socket, and

said resilient bracket comprising means being adapted to apply a force on the base of said lamp towards said reference bracket to maintain said lamp in a predetermined position relative to said reference bracket, and means adapted to exert a force on said lamp base toward said socket to hold said lamp in said socket.

6. The combination of claim including lamp ejector means comprising a lever pivoted relative to said lamp-holder and adapted to move said lamp out of said lamp-holder when said lever is moved in a predetermined manner.

7. The combination of claim 5 wherein at least one of said reference bracket and said resilient bracket comprises an entry portion bent outwardly from the face of said socket and adapted to lead said base of said lamp into position in said lampholder, and

said resilient bracket comprises a hold-down member bent at an angle less than 90 to said side wall and less than 90 to said face, and adapted to exert forces upon said base towards said face and towards said reference bracket when said lamp is in position in said lamp-holder.

8. A prefocused lamp comprising a bulb, a filament in said bulb, a base connected to said lamp, and two pins attached to said base and serving as electrical inleads for said lamp, sad base comprising means adapted to permit a resilient bracket to hold said lamp in a socket of a lampholder and against a reference bracket of said lamp-holder so that the light source of said lamp is held in a predetermined position relative to said lamp-holder, said means comprising at least one protruding mounting pad on said base located in predetermined relationship to said filament and fitting against said resilient bracket to aid in positioning said lamp, said pad being adapted to interact with a hold-down member of said lamp-holder to exert forces on said lamp base toward said socket and toward said reference bracket, and at least three positioning lugs located on the face of said base opposite said lamp and protruding a predetermined distance from said filament to accurately limit the depth of said two pins in said socket.

9. A lamp according to claim 8 wherein said base has four sides which are essentially flat except for said pads, with one of said pads being located on each of two opposite sides of said base.

10. A lamp according to claim 9 in which said pads have linear referencing edges both on their sides and on their tops when said lamp is considered to extend from the top of said base, said linear referencing edges having a predetermined position relative to said filament.

References Cited UNITED STATES PATENTS 2,082,954 6/1937 Gustin l767 2,186,184 1/1940 Tubbs 339-91 X 3,156,511 11/1964 Zillmer 339 RICHARD E. MOORE, Primary Examiner U.S. Cl. X.R. 33991, 145, 191 

